Method of removing air from a fluid pathway of a powered fluid injection system

Abstract

The present disclosure relates to a method of operating a powered fluid injection system (100; 200) to manage air detection and removal thereof from a fluid pathway (109; 255) of the powered fluid injection system (100; 200). The method comprises the steps of: a) monitoring (304) the fluid pathway for detecting any air contained therein; b) controlling (306) a pressurization sequence configured to be applied by a fluid pressurizing unit (106, 108; 240) to the fluid flowing through said fluid pathway; c) interrupting (310) the pressurization sequence if air is detected (308); d) generating a system alert (312) indicating that air has been detected and that an air removal sequence is required to be started (314); e) prompting (316) the operator to confirm that the air removal sequence can start; f) executing (318) the air removal sequence if an operator's confirmation is received by the powered fluid injection system; g) determining (320) a fluid pressure value of the fluid flowing through the fluid pathway; h) comparing (322) the determined fluid pressure value with a predefined fluid pressure threshold stored in a firmware of the powered fluid injection system, and continuing (324) the air removal sequence to completion if the determined fluid pressure value is below the predefined fluid pressure threshold, or terminating (326) the air removal sequence if the determined fluid pressure value is meets or exceeds the predefined fluid pressure threshold.

Description

[0001] DESCRIPTION

[0002] Technical field

[0003] The present disclosure relates to the field of powered fluid injection systems. In particular, the present disclosure relates to a method for removing air from a fluid pathway of a powered fluid injection system.

[0004] Background

[0005] The background of the present disclosure is introduced hereinafter with the discussion of techniques relating to its context. However, even when this discussion refers to documents, acts, artifacts and the like, it does not suggest or represent that the discussed techniques are part of the prior art or are common general knowledge in the field relevant to the present disclosure.

[0006] Many medical procedures, including diagnostic and / or interventional procedures, involve injecting a contrast media into a patient. Angiography is one example of such a procedure. Angiography is used in the diagnosis and treatment of cardiovascular conditions including abnormalities or restrictions in blood vessels. During angiography, a radiographic image of the heart or of the vascular structure is obtained by injecting contrast media through a catheter into a vein or artery of the patient. The injected contrast media can pass to vascular structures in fluid communication with the vein or artery in which the injection is made.

[0007] An injector can be used to inject contrast media into a patient in conjunction with diagnostic and / or interventional medical procedures. Contrast media is generally held at the injector within a fluid container, such as a reservoir. During a patient injection, the injector pressurizes and delivers this contrast media to the patient. To do so, in case a syringe injector is used, the latter generally drives a shaft linearly within the fluid container (i.e., the syringe), starting at one end of the fluid container and moving progressively through the fluid container to an opposite end, thereby delivering the contrast media (or part of the contrast media) present inside the fluid container. The pressurized contrast media is then conveyed along a patient tubing (typically called “patient set”) and introduced into a patient vasculature by means of a catheter or a Vascular

[0008] Access Device (VAD).

[0009] If air is detected within the patient tubing, this is generally a dangerous situation for a patient. Therefore, the injection procedure is interrupted, air present in the patient tubing is removed and then the injection procedure can be restarted after air removal.

[0010] Several methods are known for removing air from a fluid pathway of a powered fluid injector. For instance, there are procedures which automatically detect and semi-automatically remove air from a patient tubing, the semi-automatic procedures requiring the manual intervention of an operator. For example, when the injection system detects air in a given fluid pathway during an injection, the injection is automatically and immediately interrupted for allowing air removal. In detail, the injection system instructs the operator to manually close a valving means (e.g., a stopcock valve) present on the fluid pathway (i.e., the patient tubing) in order to disconnect the latter from the catheter or the VAD (and thus from the patient), while opening the fluid pathway to atmosphere, thereby collecting the fluid flowing through the pathway into a dedicated reservoir and letting the air trapped in the fluid to escape directly into the ambient. According to this semi-automatic air removal sequence, the operator must perform the manual steps of closing the valving means positioned (i.e., installed) on the fluid pathway in close proximity to the patient, and then confirming on the injection system that said closing step has been performed, e.g. by pressing a button at the injector user interface. Therefore, if the air detection system does not detect additional remaining air in the flowing fluid, the fluid injection system is ready to be armed and to restart the injection procedure after the operator has confirmed that no air is present in the fluid pathway.

[0011] However, if the user accidentally confirms that the valving means has been closed (e.g., by inadvertently pressing a confirmation button at the injector head or at a user interface of the injector remote control) without having indeed previously closed the valving means and without having fluidically disconnected the patient from the fluid injection system, very likely air will be delivered to the patient together with the fluid through the fluid pathway.

[0012] Document US 11,400,214 B2 (in the name of the present Applicant) discloses methods and systems suitable for quantifying how much contrast fluid is injected into a patient by a powered fluid injector. A controller of the powered fluid injector can receive a command from a user to begin dispensing contrast fluid. The controller may determine whether a hemodynamic pressure signal is present from a pressure sensor in fluidic connection with the vasculature of the patient. The powered fluid injector may dispense a quantity of contrast fluid in response to the command. The controller may add the quantity of contrast fluid to an injection quantity if the hemodynamic pressure signal is present just prior to and / or just after the quantity of contrast fluid is dispensed. The controller may refrain from adding the quantity of contrast fluid to the injection quantity if the hemodynamic pressure signal is not present just prior to and / or just after the quantity of contrast fluid is dispensed.

[0013] Document US 8,109,906 B2 discloses a pump system which simply and selectably controls the temperature, flow rate, flow volume, and flow pressure of a fluid being infused into a patient's body. The pump system includes a central controller and user inputs that allow for simple selection and efficient operation of the pump system, which includes manually or automatically priming the pump system to remove air, selectably controlling and rapidly adjusting the flow rate over a wide range, selectably and safely controlling the pump system temperature controls, and selectably controlling the flow pressure during delivery. The pump system includes a pump housing with a central controller and a cartridge with infusion tubing removably coupled to the pump housing.

[0014] Document EP 3,068,464 Bl discloses a system for controlled delivery of medicinal fluid which includes a fluid pathway assembly. The fluid pathway assembly has an inline flow sensor element received within the fluid pathway movable in response to fluid flowing in the fluid pathway. A flow control device is removably attached to the fluid pathway assembly and has a sensor for sensing a position of the inline flow sensor element in the fluid pathway, the position of the inline flow sensor element being representative of a second calculated fluid flow rate. The fluid pathway assembly includes a variable flow resistor adjustable to regulate a rate of fluid flow in the fluid pathway assembly. A drive mechanism attached to the flow control device is operably coupled to the variable flow resistor when the flow control device is attached to the fluid pathway assembly.

[0015] Document CA 2,763,779 (in the name of the present Applicant) discloses a method of removing air from a flow path of a medical fluid injection system. An exemplary method performed by the medical fluid injection device includes delivering a first amount of fluid to a fluid flow path, isolating fluid flow along the flow path, forming a vacuum condition up— stream of the fluid isolation, re-establishing fluid communications along the flow path, and delivering a second amount of fluid to the flow path.

[0016] With respect to the above listed prior art, and in particular with reference to document US 11,400,214 B2, the Applicant would wish to highlight that the hemodynamic pressure is indeed the patient blood pressure, and thus it has nothing to do with (i.e., it is neither representative, nor indicative of) the pressure value possessed by fluid being pressurized by a powered fluid injection system. More particularly, document US 11,400,214 B2 makes use of an invasive blood pressure sensor, and it determines whether the dispensed (pressurized) fluid was injected or not injected based on whether this blood pressure sensor detects a hemodynamic pressure signal (and thus the pressurized fluid is injected) or not (and thus the pressurized fluid is not injected) in temporal proximity to when the fluid was dispensed. Therefore, the Applicant has perceived the need of avoiding the above-mentioned drawbacks of semi-automatic air removal sequences so as to provide a powered fluid injection system which is safer for a patient undertaking a fluid injection during a diagnostic or an interventional procedure, and which is also less inclined to genuine mistakes of an operator, thereby improving the overall reliability of the fluid injection system workflow.

[0017] The Applicant has thus perceived the opportunity of making use of the pressure generated during an air removal sequence when a fluid pathway (i.e., a patient tubing) is not fluidically disconnected from a patient (in particular, from a short catheter line or a VAD associated with the patient’s vasculature) and thus not opened to the atmosphere through a valving means, said pressure generation advising the operator to verify the correct positioning of the valving means.

[0018] The Applicant has perceived the opportunity to take advantage of the remarkable difference in pressure of pushing a fluid when the fluid pathway is connected to a patient (and thus a catheter or a VAD is still at least partially fluidically connected to the patient’s vasculature) with respect to the case in which the fluid pathway is indeed opened to atmosphere.

[0019] Summary

[0020] The present disclosure is set out in the appended claims.

[0021] A simplified summary of the present disclosure is herein presented in order to provide a basic understanding thereof; however, the sole purpose of this summary is to introduce some concepts of the disclosure in a simplified form as a prelude to its following more detailed description, and it is to be interpreted neither as an identification of its key elements, nor as a delineation of its scope.

[0022] The present disclosure is directed to a method of operating a powered fluid injection system to manage air detection in a fluid pathway of said powered fluid injection system as defined in independent claim 1, while the dependent claims outline preferred and / or particularly advantageous aspects of the present disclosure. According to a further embodiment, the present disclosure relates also to a powered fluid injection system configured to manage air detection in a fluid pathway of said powered fluid injection system.

[0023] Moreover, the present disclosure is also directed at a computer program and to a computer program product to perform said method of operating.

[0024] It is to be understood that elements and features of one form of embodiment of the present disclosure may generate other forms of embodiments still falling within the scope of protection of the present disclosure.

[0025] Dependent claims outline preferred and / or particularly advantageous aspects of the present disclosure.

[0026] Brief description of the drawings

[0027] The solution of the present disclosure, as well as further features and the respective advantages, will be better understood with reference to the following detailed description thereof, provided purely by way of a non-restrictive indication, with its explanations applying by analogy to every aspect thereof (irrespectively of the context in which they occur); the description is to be read in conjunction with the accompanying drawings (wherein, for the sake of simplicity, corresponding elements are denoted with equal or similar references and their explanation is not repeated, and the name of each entity is generally used to denote both its type and its attributes, like value, content and representation). In this respect, it is expressly intended that the drawings are not necessarily drawn to scale (with some details that may be exaggerated and / or simplified) and that, unless otherwise indicated, they are merely used to illustrate the structures and procedures described herein conceptually. In addition, orientations and related position references (such as front, rear, upper, lower, lateral and so on) are to be understood in relation to a condition of use of the corresponding entities. Particularly, reference will now be made in detail to the various forms of embodiment of the present disclosure, with particular reference to the appended figures, wherein:

[0028] Figure 1 shows a pictorial representation of a powered fluid injection system wherein the solution according to an embodiment of the present disclosure may be used;

[0029] Figure 2 shows a pictorial representation of an alternative powered fluid injection system wherein the solution according to an embodiment of the present disclosure may be used;

[0030] Figures 3A-3B show an activity diagram describing the flow of activities of a fluid injection procedure including an air removal sequence according to the present disclosure, and Figure 4 (in combination with Figure 3A) shows an alternative embodiment of a fluid injection procedure including an air removal sequence according to the present disclosure.

[0031] Detailed description

[0032] Each example of the following description is herein provided merely as an illustration of the present disclosure, and it is not intended as a limitation thereof. For example, the technical features illustrated or described as forming part of one embodiment may be adopted over, or in association with, other embodiments to define a further form of implementation of the present disclosure. It is understood that the present disclosure will be inclusive of such modifications and variations.

[0033] Figure 1 schematically shows a fluid injection system 100 comprising a powered fluid injector wherein the present disclosure is implemented. However, it is pointed out that the present disclosure is not limited to the powered fluid injector shown in Figure 1, and that the present disclosure can be advantageously applied to other known and different powered fluid injectors, as for instance the powered fluid injector of the fluid injection system 200 shown in Figure 2.

[0034] In operation, the powered fluid injector can inject a quantity of fluid into a patient, for instance into a vessel of a patient via a catheter. The fluid injected by the powered fluid injector can be, for example, a contrast fluid, a non-contrast fluid (e.g., saline), or a combination thereof. By injecting a quantity of fluid into a patient, the powered fluid injector can facilitate a variety of medical diagnostic and / or interventional procedures.

[0035] According to the embodiment shown in Figure 1, the powered fluid injector includes a drive assembly housing 102 and a sleeve 104. The sleeve 104 may extend out from the drive assembly housing 102 and may be configured to receive and hold a reservoir 106. The reservoir 106 (for example in the form of a syringe) can have an internal reservoir volume containing a fluid, and a plunger 108 is provided within the internal reservoir volume. At least a portion of a drive assembly can be housed within the drive assembly housing 102. It is noted that the powered fluid injector as shown in Figure 1 is exemplary for purposes of generally describing features of a powered fluid injector, so that some details related to a powered fluid injector not relevant for the present disclosure will not be further described. Similarly, it is noted that different embodiments, with respect to the powered fluid injector as shown in Figure 1, could be used in order to perform the method of the present invention.

[0036] The drive assembly is configured to pressurize the fluid contained in the internal reservoir volume. For instance, the drive assembly may couple to the plunger 108 and drive it back and forth within the internal reservoir volume. As the plunger 108 is progressively driven within the reservoir 106, the fluid present in the internal reservoir volume can be pressurized and output from the reservoir 106 along a fluid pathway, i.e. an injection line 109 (i.e., a tubing) connecting the injector to a patient (by means of a catheter or a VAD) for delivering the pressurized fluid into the patient’s vasculature. In certain applications of the powered fluid injector, the injected fluid delivered to the patient through the fluid pathway 109 can be pressurized anywhere up to 1200 psi (i.e., about 80 bar).

[0037] The injection line, or fluid pathway, 109 may comprise a fluid circuit line 130 that connects an outlet port of the reservoir 106 and then feeds into a patient fluid circuit line 122 (i.e., a patient tubing). The fluid pathway 109 also comprises a valving means (e.g., a stopcock valve) 126, and a catheter or a Vascular Access Device (VAD) (not shown in Figure 1) having a proximal end connected to the valving means 126 and a distal end inserted into the patient’s blood vessel. The valving means 126 is configured to assume at least a first position (i.e., opened to the patient) where the fluid can flow from the reservoir 106 to the catheter or VAD and thus to the patient, and a second position (i.e., closed to the patient) where the fluid does not flow to the patient but to the “atmosphere”, i.e. outside the injection line 109, for example onto a bed of the patient or in a dedicated bowl.

[0038] The powered fluid injector can also include a control panel 110. The control panel 110 can provide a user interface for various operational aspects. For example, the control panel 110 can be used by the operator to set up various parameters and / or protocols for performing a given fluid injection procedure. In one example, the operator can interact with the control panel 110 to input injection parameters such as flow rate, injection volume (e.g., maximum volume to be injected), injection pressure (e.g., maximum pressure), rise time, and / or other injection parameters. In one embodiment, control panel 110 includes a touch-screen panel display, enabling the operator to view and modify the injection parameters. The control panel 110 can also be used to initialize the powered fluid injector (e.g., to prepare it for a patient fluid injection), or to activate certain features or sequences of operation. The control panel 110 may also provide status information, including information related to past or currently ongoing injection procedures as well as any appropriate alerts.

[0039] The control panel 110 can be controlled by one or more processors (e.g., at the control panel 110 itself and / or within the drive assembly housing 102). Such processors can also control other components, such as the drive assembly, a peristaltic pump 112, when present, and / or any sensors and detectors included at the powered fluid injector. In addition to the control panel 110, the powered fluid injector may include a hand-control device 113 for some operator inputs advantageously performed close to the patient during the injection procedure without needing to act on the user interface of the control panel 110.

[0040] The powered fluid injector can also include one or more components useful for supplying fluid to be used in an injection procedure. A container 114 can include a supply of fluid, such as contrast media, and be secured to a holder 116 at the powered fluid injector. Fluid from the container 114 can be supplied to the reservoir 106 for use during an injection procedure. For example, fluid from the container 114 can be drawn into the reservoir 106 when the plunger 108 is being retracted (e.g., moved in a direction towards the drive assembly housing 102), thereby filling or refilling the internal reservoir volume. Similarly, when the powered fluid injector includes the peristaltic pump 112, a second container 118 can include a supply of a second fluid, such as a flushing medium (e.g., saline), and be secured to a holder 120 at the powered fluid injector. When present, the peristaltic pump 112 can receive the second fluid from the second container 118 and deliver such second fluid to the patient through a further distinct fluid circuit line 132 that feeds into the patient fluid circuit line 122 of fluid pathway 109. Often times, the peristaltic pump 112 may be used to deliver non-contrast fluid at a lower pressure than that at which the drive assembly delivers contrast fluid from the reservoir 106.

[0041] The powered fluid injection system 100 further comprises an air detector 124 configured to detect air inside the fluid pathway 109. The air detector 124 may be, for example, an air column detector (ACD), and it is connected to the one or more processors of the powered fluid injector so as to provide a warning indication to the operator and to request the operator to start an air removal sequence.

[0042] The fluid circuit of the powered fluid injection system 100 further comprises a manifold valve 134 and an associated sensor 136 to control the flow of the two fluids into line 138, from the reservoir 106, via line 130, and from line 132. When the manifold valve 134 is opened to line 132 and closed to line 130, and line 138 is coupled to the patient line 122 and thus to the patient's vasculature (for example, by means of a catheter - not shown - connected to patient line 122 at the valving means 126), a pressure transducer assembly 140, which is integrated into line 132, monitors the patient's blood pressure. However, when the injector pump is activated to inject a contrast agent, the manifold valve 134 is switched to allow the relatively high pressure flow moving from the injector pump (and thus from the reservoir 106) into line 138, thereby isolating line 132 from the high pressure flow, not only to prevent backflow into line 132, but also to protect the pressure transducer of assembly 140 from exposure to the relatively high injection pressures that could damage the pressure sensor thereof.

[0043] With reference to Figure 2, a pictorial representation is shown of an alternative powered fluid injection system 200 wherein the solution according to an embodiment of the present disclosure is used.

[0044] The powered fluid injection system 200 is used in medical applications for injecting in an automatic way one or more medical fluids into corresponding patients’ vasculature (not shown in the figure). For example, the powered fluid injection system 200 is used to perform angiographic procedures involving injection of a contrast agent (to enhance a contrast of specific body features within a patient) and of a saline solution (comprising a physiological or isotonic solution).

[0045] The powered fluid injection system 200 comprises the following components.

[0046] An injection head 205 houses the components controlling a delivery of the contrast agent and of the saline solution. The injection head 205 may be mounted on a pedestal cart 210 (provided with wheels to facilitate moving the injection system 200 and with a foot brake to secure the injection system 200 in position). A support 215 (for example, a hanger at the top of a pillar projecting upwards the injection head 205) is used to support a container 120 of the contrast agent (for example, a bottle). Another support 225 (for example, a hanger projecting laterally from the injection head 205) is used to support a container 230 of the saline solution (for example, a pouch). A syringe chamber 235 is used to house a syringe 240 for the contrast agent. The syringe chamber 235 has a motor (not shown) for sliding a plunger (not shown) back and forth inside a barrel of the syringe 240. A (flexible) tube 250 connects an inlet port of the barrel of the syringe 240 to the container 220 for filling the syringe barrel with a suitable volume of contrast agent present in the container 220 (said filling step being performed by pulling the plunger of the syringe 240 in a proximal direction, i.e. from right to left in the injection system layout shown in Figure 2, thereby generating a vacuum degree which allows suction of the contrast agent into the syringe barrel). Another (flexible) tube 255 is connected to an outlet port of the syringe 240 for delivering the pressurized contrast agent (said delivering step being performed by pushing the plunger of the syringe 240 in a distal direction, i.e. from left to right in the injection system layout shown in Figure 2). A peristaltic pump 260 delivers the saline solution (in the following, reference will be made to this application, with the same considerations that may apply to any other fluid being delivered). For this purpose, the peristaltic pump 260 acts on a (flexible) tube 265 that is connected to the pouch 230 for supplying the saline solution. A T-connector 270 connects the flexible tube 255 (delivering the contrast agent) and the flexible tube 265 (delivering the saline solution) to a (flexible) tube 275 for injecting the fluids into the patient (for example, connected to a catheter or a VAD, not shown in the figure, which is previously introduced into the patient’ s vasculature, i.e. a patient’ s blood vessel like a vein or an artery). A control unit 280 controls the whole powered fluid injection system 200, including also the peristaltic pump 260.

[0047] The bottle 220, the pouch 230, the syringe 240, the tube 250, the tube 255, the tube 265, the T-connector 270 and the tube 275 are all disposable elements (for single or multiple use); therefore, they are represented in the figure in broken line to distinguish them from the actual non-disposable components of the powered fluid injection system 200. With reference now to Figures 3 A-3B, an activity diagram is shown describing the flow of activities performed by an operator and / or the powered fluid injection system for the implementation of the solution according to an embodiment of the present disclosure.

[0048] Particularly, the diagram represents an exemplary process that may be used to manage air detection (and thus an air removal sequence) in a fluid pathway of a powered fluid injection system during an injection procedure with a method 300. In this respect, each block of the shown diagram may correspond to one or more executable instructions for implementing the specified logical function on the control unit 110, 280 of the powered fluid injection systems 100, 200, respectively.

[0049] The method begins at the black start circle 302 where the processor of the powered fluid injection system starts a setup procedure which is not shown in the activity diagram for sake of conciseness since it is not strictly related to the relevant aspects of the present disclosure, said setup procedure being guided step-by-step by the processor in order to facilitate and support the operator’s activities. For example, the setup procedure involves installing at least one bottle of contrast agent and a pouch of saline solution, connecting corresponding tubes to provide a suitable fluidic communication between the reservoirs (i.e., the contrast agent bottle and the saline solution pouch) and the injection system, inserting a syringe into the syringe chamber, filling a predetermined volume of contrast agent into the syringe by moving a motor ram to act on a plunger contained within the syringe barrel, connecting a corresponding tube (provided at a syringe outlet port) to a catheter or a VAD inserted into a patient’s vasculature, entering or selecting from a drop down menu specific information about the selected contrast agent and the saline solution (e.g., selected volume, contrast agent manufacturer, contrast agent concentration, selected needle gauge), entering or selecting from a drop down menu an injection profile (i.e., an injection protocol) comprising one or more injection phases depending on the diagnostic examination to be carried out, each injection phase of the selected injection protocol being defined by predetermined values of volume, pressure and flow rate of the contrast agent and / or the saline solution to be injected. As part of the setup procedure of the powered fluid injection system, when the patient is not yet connected to the injection system fluid pathway, an initial air removal sequence is performed by the powered fluid injection system in order to remove all the air inevitably present inside all the components of the injection system.

[0050] As far as the injection procedure is setup (thus including also said initial air removal sequence) and the fluid injector is armed (i.e., the injector is ready to inject as soon as a patient is connected) at the black start circle 302, the powered fluid injection system monitors (at step 304) if air is present along the fluid pathway 109 (for sake of conciseness, reference is made only to the powered fluid injection system 100 shown in Figure 1). In fact, as an injection system safety measure, said monitoring step 304 is started and automatically performed by the injection system also when the injection system is not injecting, and thus an injection procedure is not running.

[0051] As already mentioned above, the monitoring step 304 is carried out, for instance, by means of the air column detector (ACD) 124 shown in Figure 1 that is connected to the one or more processors of the powered fluid injector in order to promptly provide a warning indication to the operator in case air is detected.

[0052] Preferably, the monitoring step 304 is performed in real-time and continuously over time so that any possible air bubble is immediately detected, notified to the injection system processor and then to the operator.

[0053] As soon as the injection system is ready, the method then passes to block 306 for controlling and managing a pressurization sequence that is configured to be applied by the fluid pressurizing unit of the injection system, e.g. by acting on the plunger 108 positioned inside the reservoir 106 or the syringe 240). Therefore, the operator can start an injection procedure (for example, by pressing a button at the injection system control panel) and an injection is started for performing a desired and programmed medical procedure for the given patient under examination (for instance, an angiographic procedure in the example at issue).

[0054] In case air is not detected, at block 308 the injection procedure proceeds to completion according to the chosen injection protocol, as indicated at black and white circle 400 shown in Figure 3B.

[0055] On the contrary, if air is indeed detected at block 308, the pressurization sequence is interrupted at block 310, and the inj ection system processor(s) generates a system alarm at block 3 Vindicating to the operator that air has been detected and that an air removal sequence is required.

[0056] Preferably, the pressurization sequence is interrupted by disabling the injector pump motor.

[0057] Preferably, the warning indication generated by the injection system comprises a visual message (e.g., a text message or a blinking icon) displayed at the control unit 110 which requires attention and response by the operator. Alternatively, the warning indication comprises a warning light (i.e., a light signal of a given color, e.g. a red light) flashing at the control unit 110 or at any easily visible position of the injection system, or an audible alert, or a combination thereof.

[0058] The warning alert at block 312 requires the injection system to move to the following block 314 according to which the operator is requested to start an air removal sequence so that the air can be safely discarded to the atmosphere and not injected into the patient’s vasculature.

[0059] Therefore, according to the air removal sequence 314, the operator is requested to disconnect the patient from the fluid pathway 109, and thus to turn the valving means 126 (e.g., a stopcock valve) from its first position (opened to the patient) into its second position (closed to the patient and opened to the atmosphere), so that the fluid present inside the fluid pathway 109 does not flow into the patient but it moves to the “atmosphere”, e.g. the fluid is typically dispensed into a dedicated collection reservoir close to the patient’s bed.

[0060] Since the powered fluid injection system does not automatically sense if the valving means 126 has been turned to its second position closed to the patient and opened to the atmosphere, the activity diagram of Figure 3 A comprises the step 316 of prompting the operator to confirm that the valving means 126 has been opened to the atmosphere and that the air removal sequence can be started. According to the embodiment of the powered fluid injection system 100 of Figure 1 or the embodiment of the powered fluid injection system 200 of Figure 2 described above, said prompting step (shown as block 316 in Figure 3 A) may comprise, for instance, a confirmation button to be prompted by the operator at the control panel 110 and at the control unit 280, respectively.

[0061] As soon as the operator confirmed that the valving means 126 is turned to its second position (and thus opened to the atmosphere), the air removal sequence is executed (as indicated at block 318 of Figure 3B).

[0062] As mentioned above, the powered fluid injection system 100, 200 does not automatically detect the current position of the valving means 126, and thus the injection system relies only on the confirmation provided directly by the operator. However, if the operator has erroneously provided this confirmation (e.g., the confirmation was given by mistake or inadvertently by the operator, or the valving means 126 was indeed turned only partially and thus the fluid pathway 109 was only partially disconnected from the patient and only partially opened to the atmosphere), the air removal sequence is started anyway, and there’s an actual risk that the air (or part of the air) present in the fluid pathway is injected into the patient.

[0063] As already mentioned above, the Applicant has perceived the need of avoiding (or at least of remarkably reducing) this risk by implementing an automatic verification procedure according to the present disclosure. In detail, after the air removal sequence is started at block 318, at block 320 the method according to the present disclosure comprises the step of determining the fluid current pressure (i.e., the pressure currently possessed by the fluid flowing through the fluid pathway 109 and measured - in real time - after the operator has confirmed that the valving means 126 is opened to the atmosphere), and then moves to block 322 to the step of comparing the determined fluid current pressure with a predetermined fluid pressure threshold that is configured at the development stage of the injection system and stored (i.e., hardcoded) into the injection system firmware. Preferably, the step 320 of determining the fluid current pressure and the step 322 of comparing are performed continuously.

[0064] The predetermined fluid pressure threshold of the given powered fluid injection system is set to be: a) above the fluid pressure value that is required to push the fluid along the fluid pathway 109 with no restriction due to the fluidic connection with the catheter or the VAD inserted into the patient’s vasculature, i.e. with the valving means 126 opened to atmosphere, but b) lower than the fluid pressure value required to push the fluid along the fluid pathway 109 when the catheter or the VAD is fluidically connected, i.e. with the valving means 126 closed to the atmosphere (i.e., opened to the patient).

[0065] The predetermined fluid pressure threshold of the powered fluid injection system is set through testing during the development and design stages of the injector, and then it is typically stored (i.e., hardcoded) into the firmware of the powered fluid injector.

[0066] Typically, the predetermined fluid pressure threshold of the powered fluid injection system depends on many factors, e.g. on the type of fluid that is injected, on the type of disposables being used (e.g., type and size of the catheter or of the VAD). Depending on the specific powered fluid injection system being used, only one single fluid pressure threshold is set (e.g., the maximum fluid pressure that would ever be generated to push the fluid through the stopcock valve to atmosphere), or, alternatively, multiple and different fluid pressure thresholds are determined (calculated) during the injector development phase and then stored into the firmware of the injection system for being retrieved during the comparing step 322 of the method of the present disclosure.

[0067] According to tests performed by the Applicant, the predetermined fluid pressure threshold is preferably comprised between 5% and 25% of the maximum allowed injection pressure of the injector of the given injection system under consideration. For example, the injector of the injection system 100 shown in Figure 1 or the injector of the injection system 200 shown in Figure 2 has a maximum allowed injection pressure of 1200 psi. Therefore, its predetermined fluid pressure threshold can be set between 60 psi (corresponding to 5% of 1200 psi) (about 4 bar) and 300 psi (corresponding to 25% of 1200 psi) (about 21 bar). For most injection systems, a fluid pressure threshold in this range is higher than the fluid pressure required to push fluid through the valving means opened to the atmosphere and lower than the fluid pressure required to push fluid through a catheter or a VAD.

[0068] In general, the injection systems deliver fluids with a set flow rate and a set pressure limit. If the injection pressure reaches the pressure limit, in order to prevent the injection pressure from exceeding the pressure limit, the injection system will take dedicated action, for instance by lowering the flow rate or by stopping the injection altogether. Many injection systems (including injection systems 100 and 200 of Figures 1 and 2, respectively) allow multiple pressure limit settings for compatibility with various catheters, VADs, or other disposable devices. All injection systems have a maximum allowed pressure limit of the injection system (i.e., a maximum allowed injection pressure of the injector of the given injection system) that is never to be exceeded during any injection. The injection systems 100 and 200 of Figures 1 and 2 each have a maximum allowed injection pressure of 1200 psi that is provided (and typically indicated in the user’s guide) by the injector manufacturer. Although a user may set lower pressure limits than 1200 psi, he cannot set a pressure limit above the maximum allowed pressure limit of 1200 psi. Therefore, the comparison step at block 322 according to the present disclosure allows the powered fluid injection system 100, 200 to determine the actual position of the valving means 126, and thus to properly determine if the powered fluid injection system is indeed disconnected from the patient, and the valving means 126 is correctly and fully opened to the atmosphere.

[0069] The step of determining the fluid current pressure (i.e., the pressure possessed by the fluid flowing through the fluid pathway 109 and measured after the operator has confirmed that the stopcock valve 126 is opened to the atmosphere) at block 320 can be performed according to different techniques. For instance, the pressure value can be indirectly determined by measuring the electrical current necessary for acting the plunger 108 within the internal volume of the reservoir 106. Alternatively, the pressure of the fluid flowing onto the fluid pathway 109 can be detected by installing a pressure sensor acting on said fluid pathway 109.

[0070] According to the comparing step performed at block 322, if the fluid actual pressure determined along the fluid pathway 109 at block 320 is lower than (i.e., below) the predetermined pressure threshold of the powered fluid injection system, then it means that the injection system has indeed been disconnected from the patient and the valving means has been set in its open condition (i.e., opened to the atmosphere). Therefore, the method according to the present disclosure is allowed to move to block 324, and thus the air removal sequence is definitely completed. Once the air purging (i.e., the air removal) is completed and no further air is detected inside the fluid pathway, typically a visual check is performed by the operator (visually looking if air bubbles are still present and visible along the pathway) and the injection system returns to the injection procedure main screen with the injector disarmed. Thus, the powered fluid injection system is ready to resume the injection and to complete it (i.e., the operator is allowed to arm again the injector and to trigger the completion of the injection), as indicated at black and white circle 400 shown in Figure 3B. On the contrary, if the comparing step performed at block 322 results in the actual fluid pressure determined along the fluid pathway 109 at block 320 being equal to or greater than the predefined fluid pressure threshold of the powered fluid injection system (i.e., if the determined fluid pressure value meets or exceeds the predefined fluid pressure threshold), this means that the injection system has not been disconnected from the patient and the valving means is still in its closed (or partially closed) condition (i.e., still at least partially in fluidic connection with the patient, i.e. opened to the patient), thereby the fluid encountering a predetermined amount of resistance due to the presence of the catheter or the VAD still in fluid connection with the fluid pathway and the patient’s vasculature. Therefore, since the fluid containing air is at risk of being delivered into the patient, the method according to the present disclosure is moved to block 326 wherein the air removal sequence is definitely terminated.

[0071] Thereafter, at block 328 the injection system notifies the operator that the air removal sequence has been terminated and the method according to the present disclosure moves back to block 316, thereby inviting the operator to immediately check the actual and incorrect position of the valving means, and to fix it.

[0072] Figure 3A in combination with Figure 4 represents a further embodiment of the method of the present disclosure that is alternative to the embodiment according to the combination of Figures 3 A and 3B.

[0073] All the method steps (and the corresponding blocks in the figures) that are indicated with same reference numbers and that are in common with the two different embodiments, indeed represent the same activities being performed in the two alternative methods of removing air from a fluid pathway of a powered fluid injection system.

[0074] Therefore, according to the alternative embodiment of the present disclosure shown in the combination of Figures 3 A and 4, after the step of terminating the air removal sequence at block 326, the method moves to a pressure reducing step at block 410. In fact, the Applicant has noticed that, if the pump motor is simply stopped in order to interrupt the injection procedure, the fluid present in the fluid pathway is not immediately stopped and it continues flowing, thereby reaching the catheter or the VAD and being injected into the patient’s vasculature, until the pressure present in the reservoir 106 (e.g., a syringe) and in the fluid pathway 109 of the injection system 100 is equalized to the patient’s blood pressure.

[0075] Therefore, in order to avoid such undesired fluid injection and to interrupt the injection procedure as soon as possible, the Applicant has found very effective to perform a pressure reducing step 410 according to which the pressure of the fluid flowing through the fluid pathway is quickly and remarkably reduced.

[0076] For instance, according to the embodiment of the powered fluid injection system 100 represented in Figure 1, the pressure exerted by the plunger 108 on the fluid present in the fluid pathway 109 is reduced by moving the pump motor in reverse, and thus by inverting the movement of the plunger 108 within the internal volume of the reservoir 106.

[0077] Moving the pump motor in reverse means that the pump motor is actually moved backwards. This backwards movement is not meant to pull any fluid into the reservoir 106 and to reverse the fluid flow, but only to remove the pressure that has been built up inside the reservoir 106 (and the fluid pathway as well), until enough pressure has been relieved so that the manifold valve 134 closes, thereby preventing the air present in the fluid pathway from entering the catheter or the VAD connected to the fluid pathway, and thus eventually from entering the patient’s vasculature.

[0078] According to tests conducted by the Applicant, during the pressure reducing step 410 the pump motor is moved backwards at 3 mL / s for up to 5 mL.

Claims

CLAIMS1. A method of operating a powered fluid injection system (100; 200) to manage air detection in a fluid pathway (109; 255) thereof, wherein the method comprises the steps of: a. monitoring (304), under the control of at least one processor, the fluid pathway (109; 255) to detect the presence of air by means of at least one air detector (124) connected to said at least one processor; b. controlling (306), under the control of said at least one processor, a pressurization sequence configured to be applied by a fluid pressurizing unit (106, 108; 240) to the fluid flowing through said fluid pathway (109; 255); c. interrupting (310), under the control of said at least one processor, the pressurization sequence if air is detected (308) by said at least one air detector; d. generating (312), under the control of said at least one processor, a system alert indicating that air has been detected and that an air removal sequence (314) is required; e. prompting (316), under the control of said at least one processor, for an operator confirmation to initiate the air removal sequence; f. executing (318), under the control of said at least one processor, the air removal sequence upon receiving operator confirmation by operating a valving means (126) of the powered fluid injection system (100; 200) for fluidically connecting said fluid pathway (109; 255) to the atmosphere; g. determining (320), under the control of said at least one processor, a pressure value of the fluid flowing through the fluid pathway (109; 255), the step of determining being performed by measuring an electrical current necessary for acting a plunger (108) within an internal volume of a reservoir (106) of the powered fluid injectionsystem (100; 200), or by measuring said fluid pressure through a pressure sensor positioned along the fluid pathway (109: 255); h. comparing (322), under the control of said at least one processor, the determined fluid pressure value with a predefined fluid pressure threshold stored in the powered fluid injection system firmware, and: continuing (324) the air removal sequence if the determined fluid pressure value is below the predefined fluid pressure threshold, or terminating (326) the air removal sequence if the determined fluid pressure value meets or exceeds the predefined fluid pressure threshold.

2. The method according to claim 1, characterized in that the step of generating a system alert (312) comprises providing a visual message, a light signal, an audible alert, or a combination thereof.

3. The method according to claim 1 or 2, characterized in that, if the air removal sequence is required to be started (314), the operator is requested to turn the valving means (126) from a first position opened to a patient into a second position closed to the patient and opened to the atmosphere.

4. The method according to any of the preceding claims, characterized in that the step of prompting (316) comprises pushing a confirmation button on a control panel (110; 280) of the powered fluid injection system (100; 200).

5. The method according to claim 3, characterized in that the step of determining (320) the pressure value of the fluid flowing through the fluid pathway (109; 255) is performed after the operator has confirmed that the valving means (126) is opened to the atmosphere.

6. The method according to any of the preceding claims, characterized in that the fluid pressure threshold is configured at the development stage of the powered fluid injection system.

7. The method according to any of the preceding claims, characterized in that the fluid pressure threshold is set to be above a pressure value required to push the fluid through the fluid pathway (109; 255) when there is no restriction due to a fluidic connection with a catheter or a Vascular Access Device (VAD) inserted into a patient’s vasculature, and lower than a pressure value required to push the fluid through the fluid pathway (109; 255) when said catheter or said Vascular Access Device is fluidically connected to said fluid pathway.

8. The method according to claims 3 and 7, characterized in that the fluid pressure threshold is set to be above a pressure value required to push the fluid through the fluid pathway (109; 255) when the valving means (126) is in its second position closed to the patient and opened to the atmosphere, and lower than a pressure value required to push the fluid through the fluid pathway (109; 255) when the valving means (126) is in its first position opened to the patient.

9. The method according to claim 1, characterized in that the fluid pressure threshold is comprised between 5% and 25% of the maximum allowed injection pressure of the injector of the powered fluid injection system (100; 200).

10. The method according to any of the preceding claims, characterized in that, after the step of terminating (326) the air removal sequence, the method further comprises the step of notifying (328) the operator that the air removal sequence has been stopped.

11. The method according to claims 1 to 9, characterized in that, after the step of terminating (326) the air removal sequence, the method further comprises a pressure reducing step (410).

12. The method according to claim 11, characterized in that the pressure reducing step (410) is performed by moving in reverse a motor of the powered fluid injection system (100; 200).

13. The method according to claim 12, characterized in that the motor is moved backwards at 3 mL / s for up to 5 mL.

14. A powered fluid injection system (100; 200) configured to manage air detection in a fluid pathway (109; 255) thereof, the powered fluid injection system comprising:• a fluid pressurizing unit (106, 108; 240) configured to apply a pressurization sequence to the fluid flowing through said fluid pathway (109; 255);• an air detector (124) and configured to monitor the fluid pathway for detecting the presence of air;• at least one processor operatively connected to the air detector and the pressurizing unit, the processor being configured to: a. control a pressurization sequence; b. interrupt the pressurization sequence upon detection of air in the fluid pathway;c. generate a system alert to notify an operator of the air detection and the need for an air removal sequence; d. prompt the operator for confirmation to initiate the air removal sequence; e. execute the air removal sequence upon receiving operator confirmation; f. determine a pressure value of the fluid flowing in the fluid pathway; g. compare the determined fluid pressure value with a predefined fluid pressure threshold stored in the powered fluid injection system firmware; and continue the air removal sequence if the determined fluid pressure value is below the predefined fluid pressure threshold, or terminate the air removal sequence if the determined fluid pressure value meets or exceeds the predefined fluid pressure threshold.

15. A computer program configured for causing a processor of a powered fluid injection system to perform the method of operating according to claims 1 to 13 when the computer program is executed by said processor.

16. A computer program product comprising one or more non-transitory computer readable storage media having program instructions collectively stored on the readable storage media, the program instructions readable by a processor of a powered fluid injection system to cause the processor to perform the method of operating according to claims 1 to 13.

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